Earthing electrode



July 28, 1970 D. MARSHALL EARTHING ELECTRODE Filed May 132, 19625I Nlw United States Patent O Int. Cl. H01r 3/06 U.S. Cl. 174-7 6 Claims ABSTRACT oF THE DISCLOSURE An earthing electrode formed of'sheathed rod sections and joined together with pins positioned in axial holes in the ends of each section, and sleeves positioned on the exterior of the rod sections at each joint. A softmetal sealing member is positioned .on each pin and Vis deformed outwards towards'the sleeves, and these members form a conductive path between the rodv sections asvthey are assembled by `the application of axialpress ure. v

This invention relates to earthing electrodes for earth return systems, particularly earthing electrodes used for heavy-duty purposes.'

The presentin'vention providesan'eicient form of earthing electrode which is strong and durable and affords increased slidit'y for'driving purposes and where the parts are tightly engaged together `and, cannot become detached. Good electrical contact is assured as well as axial reinforcement throughout the length of the electrode. Such electrodes can be made to suit any length requirement and are simpler tomanufacture than those of known forms, and thus production costs are reduced.

The present invention provides an e'arthing electrode comprising a plurality of` sheathed rod sections formed for assembly in a lengthwise manner, said rod sections having means on their ends forinterconnecting them, said means preferably including a connecting pin on one rod section for engagement with a cooperating recess on the adjacent end of another rod section and coupling sleeves for overlying the joints formed by adjacent rod sections. The arrangement is such that when axial pressure is applied to an assembly of rod sections, the connecting pins effect an expansion of the rod sections at each joint so as to lock the coupling sleeves in place together with the adjacent rod sections.

The invention is hereinafter described with reference to the accompanying drawing wherein:

FIG. l is a sectional view of an earthing electrode according to the invention, with its rod sections before assembly of the respective joints between the sections, and also showing a driving-head tool in place;

FIG. 2 is a sectional view of a single rod section showing a coupling or locating tool positioning a coupling sleeve and effecting a preliminary expansion of the end of the rod section to secure the sleeve in place for assembly of the other parts of the joint;

FIG. 3 is a sectional view of the earthing electrode of FIG. 1 in its assembled form;

FIG. 4 is a cross section on line 4-4 of FIG. 3; and

FIG. 5 is a fragmentary cross section of a modified construction of a rod section with a reduced diameter.

The earthing electrode according to the invention comprises any number of rod sections each consisting of a metallic, preferably steel rod 5 having a preferably copper sheath or cladding 6. The rod sections 5, 6 each have an axially bored hole 7 therein extending from both extremities to a suitable extent, governed by the length of locating and expanding pins 8. In some cases it is necessary to provide for end clearance so that said pins 8 do not bottom in their holes 7 which would interfere 3,522,359 Patented July 28, 1970 ice with the pressure required to effect the expansion of an expandable sealing member 11 later described.

These holes 7 are adapted to register in line on assembly of the rod sections 5, 6 and are each provided with a mouth recess 9 suitably shaped as shown in the drawings.

The pins 8 are preferably of steel rod or of any other material suited to the purpose, and in some cases (not shown) may have tapered or chamfered ends.

Coupling sleeves 10 are used to assemble the rod sections, which are of cylindrical form and preferably of copper and of a length to overlap the joints where they are placed, and to extend along the rod sections 5, y6 to a suitable extent to form a firm connection. The sheaths 6 and the coupling sleeves 10 may be formed of copper, titanium, stainless steel, aluminum or any other suitable non-corrosive conductive material.

The aforementioned expandable sealing member 11 is preferably of soft copper of bush-like form and may be outwardly curved or bowed towards the ends as shown in FIG. 1 to facilitate the expansion thereof, and its bore is such as vto fit over the pin 8.

An earth-penetration or driving member 12 of pointed form has a stem 13 whereby it is affixed in the end hole 7 of one of the rod sections 5, 6 and may have a driving fit therein so that it is securely retained in place.

To facilitate the assembly of the coupling sleeves 10 a coupling or locating tool as shown in FIG. 2 may be provided which consists of a flanged head 14 the flange of which is of a diameter to extend beyond that of the associated sleeve 10, and it has a rod-like engaging stem 15 adapted to loosely pass through the bore of the coupling sleeve 10 and having its end shaped at 16 for engagement in the mouth recess `9 of the respective ones ofrod sections 5, 6.

The coupling tool when used in the assembly of the rod sections 5, 6 is inserted in one end of a coupling sleeve 10 which is forced over a rod section 5, 6 as seen in FIG. 2 so that it is suitably positioned thereon for a joint to be completed and pressure applied to the coupling tool. Thus the recessed end of the related rod section 5, 6 is expanded, causing said sections to be tightly engaged with said coupling sleeve 10 and retain same in place.

The locating tool 14, 15, 16 is then withdrawn and the locating pin 8 with the expandable member 11 sleeved thereover dropped into the hole 7 in the end of the rod sections 5, 6 as shown in FIG. l. The next or second electrode rod section 5, 6 is placed in position with the pin 8 entered in the hole 7 of said second section. When assembly of two or more rod sections of an electrode is completed endwise pressure is exerted on the earthing electrode to force the adjacent ends of the rod sections towards one another so that the expandable member 11 is squashed between them, expanding outwardly as seen in FIG. 3 and extending into the mouth recesses 9 of the holes 7 as well as expanding out against the coupling sleeve 10.

At the same time the endwise pressure exerted on the pins 8 causes same to outwardly expand the rod ends which tightly engage with the coupling sleeves 10 and so securely lock the parts together at the joints in a manner ensuring good electrical contact and conductively throughout the length of an electrode composed of the rod sections 5, 6. The pins 8 form an axial reinforcement, and the drive is taken along the center of said electrode.

To exert pressure on the assembled electrode sections va convenient tool termed a driving head may be provided which is shown in FIG. l. It consists of a head portion 17 having a circular recess 18 leading in from the underside and of a diameter to fit over the top end of rod sections 5, 6. A driving pin 19 is axially affixed in said recess 18 and is adapted to slidably fit in a rod hole 7.` Pressure can be applied to the driving head by a hand hammer or other suitable means to effect the bonding together of the electrode sections as before explained after which the driving head is removed. This driving head 17, 18, 19 can be used to drive an electrode into the ground.

In the case of mechanical driving, pneumatic or power driven tools may be used and driving pins provided to suit the particular tool used.

The electrode rod sections 5, 6 may be formed in uniform lengths for assembly, or made in varied interchangeable lengths to provide for length adjustmer t, and the copper sheathing may be effected in any suitable known manner.

The coupling sleeves 10 may in some cases be of the capillary fitting type, adapted to be fused in place by heat application to improve the joint, although this is not thought necessary.

4In some cases, as shown in FIG. 5, the rod sections may be reduced in diameter at and adjacent the locations of tting together so that when the coupling sleeves are fitted in place the outer peripheral surfaces are not substantially enlarged, and a ush or near flush effect is obtained at the joints.

In the afore-mentioned arrangement an enlargement 20 is formed in the end of the recess 7 either by machining or swaging down the end of the rod section to provide a reduced-diameter outer section 21.

Iclaim:

1. An earthing electrode comprising a plurality of metallic rod sections joined together, each rod section having an axial hole at each end, a connecting pin extending into adjacent holes on adjacent rod sections and being an interference fit therein, a close-titting coupling sleeve positioned on the electrode at each joint between said adjacent sections at each joint and extending therealong, and a soft-metal sealing member positioned around each pin, the arrangement being such that lwhen axial pressure is applied to said rod sections each pin is forced into its co-operating axial hole, thereby deforming said rod sectionsoutwards against the interior of said coupling sleeves to lock the latter on said rod sections, and said sealing members are compressed and expand outwardly at said joints towards said coupling sleeves and form a conductive path between said rod sections.

2. The earthing electrode according to claim 1, wherein the ends of said rod sections around said pins and said axial holes are provided with respective niches adapted to receive parts of said sealing members as they are compressed. t t

3. The earthing electrode according to claim 1, wherein said sealing members are outwardly curved between their ends.

4. The earthing electrode acc-Ording to claim 1, further comprising a pointed earth driving member affixed to the lowermost rod` section in the assembled electrode.

j 5. The earthing electrode according to claim 1, wherein said axial holes have enlargements towards their ends, allowing the ends of said pins to bevdeformed during assembly ofthe electrode and expand into said enlargements. v

6. The earthing electrode according to claim 5,`wherein said enlargements include swaged-down portions in the ends of said rod sections so that when said coupling sleeves are positioned thereon their diameter corresponds to that of said adjacent rod sections. v

References Cited UNITED STATES PATENTS 2,039,167 4/1936 Hopkins 287--2`X 2,147,829 v2/ 1939 Daniels 174-7 X `2,446,300 8/1948 Nelson et al 174--7 'FOREIGN PATENTS 1,341,679 `9/1963-` France. LARAMIE E. AsKrN, Primary Examiner 

